Metallurgical device for treating molten metal

ABSTRACT

A metallurgical unit device containing scrap metal briquettes impregnated with magnesium metal has been prepared for treating molten metal which may be lowered into and raised from the molten metal without having to employ plunging bells and the like for maintaining the briquettes submerged in the molten metal.

United States Patent [191 Easwaran [4 1 Sept. 2, 1975 METALLURGICAL DEVICE FOR TREATING MOLTEN NIETAL [75] Inventor: Jairaj Easwaran, Toledo, Ohio [73] Assignee: NL Industries, Inc., New York, NY.

[22] Filed: Aug. 12, 1974 [21] Appl. No.: 496,648

[52] US. Cl. 266/34 T; 75/53 [51] Int. Cl C2lc 7/00 [58] Field of Search 75/53-58; 266/34 T [56] References Cited UNITED STATES PATENTS 3/19l6 Naylor et al. 266/34 T 2,809,886 10/1957 Klingbeil 266/34T Primary Examiner-Gerald A. Dost [57] ABSTRACT A metallurgical unit device containing scrap metal briquettes impregnated with magnesium metal has been prepared for treating molten metal which may be lowered into and raised from the molten metal without having to employ plunging bells and the like for maintaining the briquettes submerged in the molten metal.

7 Claims, 5 Drawing Figures METALLURGICAL DEVICE FOR TREATING MOLTEN METAL BACKGROUND OF THE INVENTION In the past, when molten metals such as molten iron, are treated with treating agents, such as magnesium metal and the like, one method of treatment comprises forming magnesium metal into massive bodies with coke or other alloying metal compositions, and these bodies are introduced into the molten metal by placing them under a plunging bell which holds the magnesium containing briquettes under the surface of the molten metal, since these briquettes have a lower density than that of molten iron.

It would be desirable to obtain a type of unit which could by itself be introduced into the molten metal without having to employ plunging bells and the like which are expensive to use.

SUMMARY OF THE INVENTION The instant invention provides for a metallurgical unit device comprising:

1. a stack of scrap metal briquettes impregnated with magnesium metal placed in a closed metal container toform an assembly which is protected from the atmosphere.

2. the stack of briquettes in the assembly contain apertures which are in alignment in order to permit a rod to be inserted through the apertures.

3. the briquettes are held in place on the rod by pins or plates attached to the rod and positioned at the top and bottom of the stack of briquettes.

4. this assembly contains either removable tight fitting covers on the top and bottom of the container which are removed when the rod is to be inserted through the assembly.

5. or the stack of briquettes are placed on the rod and both the briquettes and the rod are inserted in the metal container, the upper end of the rod protruding through the top of the container.

The metallurgical unit device comprises either 1. a stack of briquettes contained in the metal container and a rod extending through the container,

2. the briquettes are stacked on a rod and the briquettes and the rod are encased in the metal container.

When the assembly comprises a stack of briquettes placed in the metal container, this assembly may be stored and shipped when the removable tightly fitting covers are used to protectthe assembly from the atmosphere. Since the removable covers are aligned with the apertures in the stack of briquettes, the covers may be removed and a rod may be inserted through the assembly to form the metallurgical unit device of the instant invention.

An alternate unit device-comprises: a stack of briqtiettes positioned on a rod and the briquettes and the rod are both encased in a metal container, the upper end of the rod protruding through the top of the container. This unit device also may be stored, shipped or used in this configuration. it

DESCRIPTION oemE'oRAvl/mos Referring to the drawings, FIG. I is a perspective view of a donut-shaped scrap iron briquette impregnated with magnesium metal.

FIG. 2 is a vertical cross-section of an assembly of scrap metal briquettes enclosed in a metal container.

FIG. 3 is a perspective view of a rod containing cross members to maintain the assembly on the rod, and

FIG. 4 is a perspective cut away vertical view of the metallurgical unit device in which the scrap metal as sembly is maintained on the rod which is inserted through the assembly.

FIG. 5 is a vertical cross-section of another form of the metallurgical unit device which is also included in the instant invention.

In FIG. I, a compressed porous scrap metal briquette I0 is impregnated with magnesium metal. The briquette contains an aperture Ill, thereby producing a donut-shaped briquette. In FIG. 2 a stack of donutshaped briquettes 20 are placed in a container 21 which has end closures 22, having central apertures 22a provided with removable tight fitting covers 23. The aperture 24 in the donut-shaped briquettes 20 are positioned in alignment with the apertures in the end closures 22 of the container 21., thus forming an assembly.

In FIG. 3, a rod 31 which is to be inserted through the assembly contains cross members comprising pins 32 in order to retain the assembly on the rod.

In FIG. 4- is shown the assembly comprising the donut-shaped briquettes 40 stacked in the container 41 and the assembly is positioned on the rod 42 and maintained on the rod by pin 43 at top and bottom (not shown) of the container.

In FIG. 5 is shown another form of the metallurgical device in which a stack of donut-shaped briquettes 51 are positioned on a rod 52. The briquettes are held on the rod by pins 53 at the top and bottom of said stack. The rod and the briquettes are then placed in a metal container 54 containing a top end closure 55, and the top end of the rod 56 protrudes through the top end closure of the container. Ceramic cement 57 seals the opening where the rod extends through the container top.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The compressed porous scrap metal briquettes used in the instant invention are those which are prepared from scrap steel or ductile iron turnings which are compressed or compacted to produce a porous scrap metal briquette having a density of from 25% to 50% of the density of iron metal. Scrap steel, turnings having length from 1/16 inch up to 9 inches, widths from 1/64 to 1 inch, and thicknesses from 1 to mils are particularly satisfactory. These scrap metal pieces when piled together should have a density less than 15% of the density of iron metal. .In this particular invention, the briquettes are compressed in dies to form, preferably, donut-shaped briquettes. These briquettes are then immersed in molten magnesium metal and the molten magnesium impregnates the network of compressed metal pieces to form the magnesium impregnated briquettes.

The preparation of these compressed porous scrap metal briquettes infiltrated with magnesium metal throughout the network of metal pieces is more fully described and claimed in co-pending US. patent application, Ser. No. 385,584, filed Aug. 3, 1973, and which is assigned to the same assignee as the instant applica- In preparing the metallurgical unit device of the instant invention, which is used to treat molten metal by lowering and raising the device in molten metal, a briquette assembly device is first prepared as follows:

A number of donut-shaped briquettes are stacked one upon another and the stack is placed into a metal container. The holes in the briquettes are aligned with one another and with the bottom and top covers of the container. These covers are tight fitting and removable.

When the donut-shaped briquettes are placed in the metal container and the container covers are used to tightly close the container, this assembly is then ready for shipping or for storage, since the donuts are protected from the atmosphere. This assembly may be used in any manner to treat molten iron.

This invention also contemplates the preparation of a metallurgical unit device which includes the use of the briquette assembly described above. In this device the top and bottom covers are removed from the container and a rod is inserted through the entire assembly. The assembly is held on the rod by plates or pins which are attached to the rod and are positioned at the top and bottom of the container.

Another form of the metallurgical unit device which may also be used contains the stack of briquettes positioned on a rod and the briquettes and the rod are encased in a metal container, the upper end of the rod protruding through the top end of the container.

If metal rods are employed, they should be coated with a refractory cement to prevent them from melting immediately when they are placed in the molten iron. If desired, graphite rods may also be employed.

These metallurgical unit devices may then be used by lowering either of the entire units into the molten iron and the unit is held below the surface of the molten metal.

Duringthe first minute, the metal container starts to dissolve in the molten metal and the magnesium metal in the briquettes starts to react with the molten iron and thereby reduces the sulfur content of the molten metal.

Since the magnesium metal is infiltrated into the porous scrap metal briquette, the release of the magnesium metal is very rapid, but it is not violent. After 3 or 4 minutes most of the magnesium metal is dissolved, and after 5 or 6 minutes the scrap metal itself and the metal rod starts to melt in the molten metal.

The metallurgical unit devices may be lowered and raised from the molten metal when desired.

In order to describe more fully the instant invention, the following procedures were carried out to produce the metallurgical unit device containing the assembly.

Scrap metal donut-shaped briquettes were prepared as follows:

Scrap steel turnings having a density of that of iron metal had the following individual piece size ranges:

length l/I6-9in. width l/64- l in. thickness 1 100 mils.

In order to prepare each donut-shaped briquette, 22.4 lbs. of these steel turnings were placed in a ringshaped die measuring OD X 5 ID X 6 inches thick. These turnings were then compressed at a load of 1,000 tons maximum (6.4 tons/sq. in.) to produce a donutshaped briquette measuring 15 OD X 5 ID X 1- /2 inches thick. The density of the metal network was 3.29 g/cc and the briquettes had a porosity of 58%.

These donuts were then degreased in an oven at 1000 F and were then submerged in molten magnesium metal to impregnate the metal network with the magnesium metal. The average amount of magnesium in the briquettes was 30% by weight.

A plurality of these donut briquettes were placed in a steel drum which was equipped with removable tight fitting top and bottom covers.

This assembly was now ready for use, for storage or for shipping.

In this particular operation the assembly device was used to prepare the metallurgical unit device of the instant invention as follows:

The top and bottom covers of the assembly were removed and a rod was inserted through the entire assembly and the assembly was held on the rod by a pin placed on the rod at the bottom of the assembly and a plate fastened to the rod at the top of the assembly. The rod was coated with a ceramic cement.

The entire metallurgical device containing a stack of 15 donut-shaped briquettes, each averaging 10 pounds of magnesium, was lowered into a ladle containing 230 tons of molten iron. The amount of magnesium in the briquettes added per ton of molten iron was 0.65 lbs.

The reaction was rapid, but not violent and was completed in four minutes. After 8 minutes both the scrap metal briquettes and the rod were also dissolved.

The initial sulfur content of the iron was 0.041% and the final sulfur content was reduced to 0.023%.

Similar results may also be obtained when the metallurgical unit device comprises both the briquettes and the rod encased in the metal container.

These metallurgical unit devices are simple and economical to prepare. They are also uniform in composition, and therefore reproducible results areobtained when used to desulfurize molten iron or to make nodular iron. These unit devices employ iron or steel as the carrier of the magnesium, and therefore do not introduce foreign substances which have to be removed from the molten iron. The use of these unit devices produce a rapid release of the magnesium metal into the molten iron without producing a violent reaction.

While this invention has been described and illustrated by the examples shown, it is not intended to be strictly limited thereto, and other variations and modifications may be employed within the scope of the following claims.

I claim:

1. An assembly for use in a metallurgical unit device for desulfurizing iron, said assembly comprising a stack of scrap metal briquettes impregnated with magnesium metal placed in a closed metal container to form said assembly, said closed metal container containing apertures in the top and bottom sections of said container, the apertures in said container having removable having tight fitting covers, said stack of briquettes also having apertures aligned with the apertures and the covers in said container, said briquettes protected from the atmosphere by said container.

2. An assembly for use in a metallurgical unit device for desulfurizing molten iron, said assembly comprising a stack of scrap metal briquettes impregnated with magnesium metal placed in a closed metal container to form said assembly, said closed metal container having end closures, said end closures having apertures having removable tight fitting covers, said stack of briquettes also having apertures aligned with the apertures in said end closures, said briquettes protected from the atmosphere by said container.

3. A metallurgical unit device useful for desulfurizing molten iron comprising a stack of scrap metal briquettes impregnated with magnesium metal placed in a metal container to form an assembly, said briquettes having apertures aligned with one another and with container openings in the top and bottom of the containers, a rod inserted through said apertures and cross members positions on said rod at the top and bottom of said container to hold said assembly on said rod.

4. A metallurgical unit device useful for desulfurizing molten iron comprising a stack of scrap metal briquettes impregnated with magnesium metal placed in a metal container to form an assembly, said container having end closures, said end closures having apertures, said briquettes also having apertures aligned with one another and with the apertures in said end closures,

a rod inserted through said apertures and cross members positions on said rod at the top and bottom of said container to hold said assembly on said rod.

5. A metallurgical unit device according to claim 4 in which the rod is metallic iron and said rod is coated with a ceramic cement.

6. A metallurgical unit device according to claim 4 in which the rod is graphite.

7. A metallurgical unit device comprising a stack of scrap metal briquettes impregnated with magnesium metal positioned on a rod, said rod containing cross members at the top and bottom of said stack to hold said stack on said rod, said stack and said rod inserted in a metal container to protect said stack from the atmosphere, the upper end of said rod protruding through the top of said container, and ceramic cement sealing the junction of said cover and said rod from the atmosphere. 

1. AN ASSEMBLY FOR USE IN A METALLURGICAL UNIT DEVICE FOR DESULFURIZING IRON, SAID ASSEMBLY COMPRISING A STACK OF SCRAP METAL BRIQUETTES IMPREGNATED WITH MAGNESIUM METAL PLACED IN A CLOSED METAL CONTAINER TO FORM SAID ASSEMBLY, SAID CLOSED METAL CONTAINER CONTAINING A PERTURES IN THE TOP AND BOTTOM SECTIONS OF SAID CONTAINER, THE APERTURES IN SAID CONTAINER HAVING REMOVABLE HAVING TIGHT FITTING COVERS, SAID STACK OF BRIQUETTES ALSO HAVING APERTURES ALIGNED WITH THE APERTURES AND THE COVERS IN SAID CONTAINER, SAID BRIQUETTES PROTECTED FROM THE ATMOSPHERE BY SAID CONTAINER.
 2. An assembly for use in a metallurgical unit device for desulfurizing molten iron, said assembly comprising a stack of scrap metal briquettes impregnated with magnesium metal placed in a closed metal container to form said assembly, said closed metal container having end closures, said end closures having apertures having removable tight fitting covers, said stack of briquettes also having apertures aligned with the apertures in said end closures, said briquettes protected from the atmosphere by said container.
 3. A metallurgical unit device useful for desulfurizing molten iron comprising a stack of scrap metal briquettes impregnated with magnesium metal placed in a metal container to form an assembly, said briquettes having apertures aligned with one another and with container openings in the top and bottom of the containers, a rod inserted through said apertures and cross members positions on said rod at the top and bottom of said container to hold said assembly on said rod.
 4. A metallurgical unit device useful for desulfurizing molten iron comprising a stack of scrap metal briquettes impregnated with magnesium metal placed in a metal container to form an assembly, said container having end closures, said end closures having apertures, said briquettes also having apertures aligned with one another and with the apertures in said end closures, a rod inserted through said apertures and cross members positions on said rod at the top and bottom of said container to hold said assembly on said rod.
 5. A metallurgical unit device according to claim 4 in which the rod is metallic iron and said rod is coated with a ceramic cement.
 6. A metallurgical unit device according to claim 4 in which the rod is graphite.
 7. A metallurgical unit device comprising a stack of scrap metal briquettes impregnated with magnesium metal positioned on a rod, said rod containing cross members at the top and bottom of said stack to hold said stack on said rod, said stack and said rod inserted in a metal container to protect said stack from the atmosphere, the upper end of said rod protruding through the top of said container, and ceramic cement sealing the junction of said cover and said rod from the atmosphere. 